Shortly after Spicer's statements, a Quinnipiac poll announced that American voters — 71 percent across every demographic — oppose a federal crackdown on states that have legalized marijuana for medical or adult use; 59 percent say marijuana should be legal.

“I am disappointed and, frankly, somewhat shocked at the White House’s latest remarks in regard to a possible crackdown on states that have legalized marijuana. Trump ran for president under the pretense of states’ rights. Cannabis has proven to be a billion-dollar industry in Colorado, creating thousands of new jobs and helping to boost our economy. A unilateral decision to take away states’ rights would be detrimental to an already divisive country, and end up driving the industry into the hands of the drug cartels.”Michael GurtmanOwner, Best Day Ever

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Medical marijuana is now legal in 28 states, Guam, the District of Columbia and Puerto Rico.

Colorado and Washington in 2012 became the first states to legalize recreational marijuana for personal use. Now recreational use is legal in eight states and the District of Columbia, whose populations are 69 million people, almost 20 percent of the U.S. population.

Michael Gurtman, owner of Aspen's newest marijuana dispensary, Best Day Ever, says it's a states' rights issue, as President Trump did while on the campaign trail last year.

"I am disappointed and, frankly, somewhat shocked at the White House's latest remarks in regard to a possible crackdown on states that have legalized marijuana," Gurtman said. "Trump ran for president under the pretense of states' rights. Cannabis has proven to be a billion-dollar industry in Colorado, creating thousands of new jobs and helping to boost our economy. A unilateral decision to take away states' rights would be detrimental to an already divisive country, and end up driving the industry into the hands of the drug cartels."

all about the Benjamins

The Obama administration in 2013 prohibited the Department of Justice from spending money on medical marijuana enforcement, saying it would not intervene in states' marijuana laws as long as they keep the drug from crossing state lines and away from children and drug cartels.

"Most of what he wants to do has already been defunded," Mitchell said.

But that policy could be rewritten by new Attorney General Jeff Sessions, who has consistently said he opposes legal marijuana.

"Marijuana is a Schedule I controlled substance," explained Jeff Dorschner, public affairs officer with the United States Attorney's Office in Denver. "We prosecute marijuana cases, but through the lens of official (Justice Department) guidance called the Cole Memo. If and when (the Justice Department) sends U.S. Attorneys updated, revised or different guidance we will adjust accordingly."

"I was concerned that President Trump appointed Sessions as the attorney general. That begins to effect how other attorneys general view their jobs," Mitchell said.

Trump has said consistently he believes marijuana is a states' rights issue.

"When it comes upending not only state laws but in some cases state Constitutional amendments, you can bet that whatever Attorney General Jeff Sessions does will have to pass through the White House," said John Hudak, a drug policy expert with the Brookings Institution.

"They are trying to make sure that adults who choose to purchase marijuana know what they're getting," Hudak said.

The vast majority of Americans agree that the federal government has no business interfering in state marijuana laws, said Mason Tvert, communications director with the Marijuana Policy Project.

"This administration is claiming that it values states' rights, so we hope they will respect the rights of states to determine their own marijuana policies. It is hard to imagine why anyone would want marijuana to be produced and sold by cartels and criminals rather than tightly regulated, tax paying businesses," Tvert said in a statement.

California was the first state to flout the U.S. Controlled Substances Act when, in 1996, voters there approved marijuana for medical use. Federal law prohibited marijuana for all uses then, and still does.

However, three presidents throughout the past 20 years have concluded that the Justice Department's time and resources are best spent pursuing large drug cartels, not individual users of marijuana.